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Update on chapter 3 notes.

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Philippe Pittoli 2025-02-12 07:48:13 +01:00
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notes/chapter3-page-tables
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@ -76,3 +76,10 @@ Before setting satp, instructions use phy@.
Each CPU its own satp so each CPU can handle user code. Each CPU its own satp so each CPU can handle user code.
XV6 = 1 page table per process and 1 page table for the kernel XV6 = 1 page table per process and 1 page table for the kernel
XV6 kernel page table:
- direct mapping for most pages
- no direct mapping for the trampoline page
- no direct mapping for stacks' pages
=> these pages are related to the processes (`kstack` in the `proc` structure)
=> the kstack is followed by an invalid guard page (PTE_V not set)
to prevent memory corruption from stack overflows